Welcome to the new version of the Patents Manual. Please note there are changes to the numbering and sequence of the chapters and pages in the manual. You are encouraged to take the time to explore and familiarise yourself with this new structure. Assessment of Inventive Step

Date Published


In this section, considerations which need to be regarded when applying the problem-solution approach for assessing whether an invention is obvious will be discussed. The problem-solution approach itself will be explained including the following considerations:

  • Determining the problem;
  • Formulating the question for assessing whether an invention is obvious in light of the factual situation;
  • Avoiding ex post facto analysis;
  • Identifying the relevant person skilled in the art; and
  • Identifying what information constitutes common general knowledge.

Problem-solution approach

An approach used by the courts to assess whether an invention involves an inventive step is the "problem-solution" approach. This approach is based on the question of whether the claimed invention would have been obvious to a person skilled in the relevant art when faced with a particular problem (HPM Industries Pty Ltd v Gerard Industries Ltd 98 CLR 424 at page 437). The approach is the preferred one to apply when considering inventive step, as it reduces the risk of ex post facto analysis (see below) and helps identify all the issues relevant to establishing lack of inventive step.

Applying the problem-solution approach

​​​​​​​The problem-solution approach involves the following steps:

a. Construe the specification under examination and determine the problem that the claimed invention solves (see Initial considerations Determining the problem for assessing inventive step below).

b. Identify the person skilled in the art in the field of the problem (see The person skilled in the art).

c. Determine, where applicable, whether in the context of the problem, any pieces of prior art information under consideration are such that the person skilled in the art could be reasonably expected to have combined them (see The person skilled in the art)

d. Determine the relevant common general knowledge (see The common general knowledge).

e. Determine whether, in the context of the problem, the claimed invention would have been obvious to the person skilled in the art.  The question of obviousness can be formulated in one of the following ways:

  • Asking whether it would have been a matter of routine to proceed from the CGK and relevant prior art information to the claimed invention; 
  • Using the “Cripps question” approach; or
  • Asking whether the claimed invention is one of:
    • a technical equivalent;
    • a workshop improvement;
    • an obvious selection or special inducement; or
    • an obvious combination of features of common general knowledge.

f. Consider whether:

  • the prior art information teaches away from the solution;
  • the invention overcomes practical difficulties in seeking the solution; and
  • the invention resides in identifying the "real nature" of the problem (see Determining the problem for assessing inventive step below​​​​​​​).

g. If relevant, consider whether there has been a prior perceived need using the tests of:

  • long-felt need;
  • failure of others;
  • copying of invention in preference to prior art; and
  • commercial success.

It is noted that these tests are secondary indicators or 'signposts' of inventive step.  The question of whether or not the claimed invention is obvious still needs to be addressed.

h. An objection of lack of inventive step only arises where it can be shown that a person skilled in the art would, in solving the problem, have taken the necessary steps to reach the claimed solution. In practice, this will be the case if the requirements under c. and e. are met, and those under f. and g. are not met.

In practical terms, examiners do not need to make a detailed analysis of every issue in each procedural step. Rather, examiners are to identify all relevant issues and explain these issues in an inventive step objection.

​​​​​​​For example, a citation which is clearly a mere technical equivalent (in the context of the problem) of the claimed invention must presumably have fully solved the problem. That is, the only issues are whether the difference is a technical equivalent in the context of the problem and whether the technical equivalent is common general knowledge.

Examiners need to be aware to avoid including any part of the solution in the phrasing of the problem because this could result in an ex post facto analysis of inventive step.

Ex Post Facto Analysis

Unlike courts, examiners do not have access to evidence from the person skilled in the art.  Instead, they are required to put themselves 'in the shoes of the skilled worker' and make their own assessment of what the notional skilled worker was likely to have done at the priority date. In doing so, they are to assess "obviousness" based on their own knowledge and balance of probability considerations, see Application of the Balance of Probabilities in Examination.

Such assessment can be difficult because examiners will inevitably know the solution (that is, claimed invention) to the problem the invention is seeking to address. Examiners must set that knowledge aside in their assessment of inventive step and be aware that considerations of whether a claim is obvious can be coloured by:

  • ex post facto analysis;
  • judging the merit of the invention;
  • the motivation for the invention;
  • failing to recognise that an inventive step requires no more than a scintilla of invention;
  • failing to determine the common general knowledge appropriate to the person skilled in the art; and
  • failing to consider all relevant issues.

Courts have also discussed the problem of ex post facto dissection of the invention which has been stated as not helpful in resolving the question of obviousness (Meyers Taylor Pty Ltd v Vicarr Industries Ltd (1977) 137 CLR 228 at page 242).

​​​​​​​Examiners are to remember that the question of obviousness is not ex post facto reasoning which involves taking the known solution and working backwards to the problem by a succession of apparently easy steps. In other words, the analysis is not one of reconstruction of an inventive process step by step, with each step being obvious in itself and when it is known, must be taken in a certain direction (Palmer v Dunlop Perdriau Rubber Co. Ltd (1937) 59 CLR 30 at page 61)

Determining the problem for assessing inventive step

Problem determined by reference to common general knowledge and prior art information

The knowledge or information which can be attributed to a skilled person for considering the question of obviousness will affect the answer. This includes knowledge of the problem being addressed by the patent specification. If the problem is itself common general knowledge, or knowledge that is s.7(3) information, then knowledge of the problem will be attributed to the skilled person for the purposes of assessing obviousness.  However, if the problem cannot be attributed to the skilled person in either of these ways, then it not permissible to attribute knowledge of the problem on the basis of the inventor’s “starting point” which might be gleaned from a reading of the specification as a whole (AstraZeneca AB v Apotex Pty Ltd (2014) FCAFC 99 at paragraphs 202 and 203; 107 IPR 177).

Problem is explicitly stated in the specification

When determining the problem, examiners are to have regard to the specification. Specifications usually discuss the prior art and identify difficulties with that art. The specification may explicitly state the prior art difficulties that the claimed invention overcomes and identify the problem solved by the invention. 

Problem can be inferred from the specification

Where there are no explicit statements in the specification which state what is the problem solved by the invention, examiners are to infer the problem. The considerations for such an inference include the:

  • stated difficulties with the prior art;
  • scope of the claim; and
  • statement(s) of an "object of the invention".

Where there is no specific reference to difficulties with the prior art or objects of the invention, examiners may be able to deduce the problem by reading the specification as a whole, including the claims, and determining what contribution is made by the essential features of the broadest independent claim, taking into consideration the common general knowledge. The problem the claimed invention was "intended" to solve can be viewed as the task of attaining that contribution.

A specification may have several well-defined objects, or problems, with only some of these solved by the independent claim. In such cases, examiners are to identify the problem associated with the independent claim. If that claim is found to lack an inventive step, dependent claims should be considered in the context of the further problems associated with them.

Arguments that the problem identified is not part of the common general knowledge or prior art information may arise during examination at further report stages. Examiners need to consider these arguments on their merits and apply balance of probability considerations (see Application of the Balance of Probabilities in Examination).

Does the claim solve the identified problem?

Having determined a problem, examiners are to:

  • ascertain from the specification what features are necessary to solve the identified problem;
  • check that the claim under consideration defines all of those features; and
  • what the identified problem does is not solved by the claimed invention, the problem will have to be redetermined to one that the claim solves.

Amendment of the problem

In response to an examination report, the applicant may (apart from simply filing submissions rebutting the inventive step objection in the report) amend the problem, amend the claims, or delete all reference to the problem. These sorts of amendments may be more difficult after following the Raising the Bar Act 2012 amendments. Examiners will need to ensure any such amendments are allowable under s102 of the Patents Act 1990.

If the applicant amends the problem, and the amendments are allowable, examiners should proceed using the new problem, unless the amended problem is inconsistent with either the description or the relevant claim.

If the amended claims provide a different solution to the problem originally identified, examiners should consider whether the original problem is still applicable and if not, redetermine the problem.

In any case where the problem is amended, examiners should consider whether the amendment gives rise to no more than a "bonus effect", see Tests for inventive step.

Invention in identifying the “real nature” of the problem

An inventive step can arise where:

  • a problem was known;
  • the cause of that problem was unknown at the priority date; and
  • the inventor has identified the cause of the problem - the "real nature" of the problem.

In this situation, “the perception of the true nature of the problem was the inventive step which, once taken, revealed that straightforward experiments will provide the solution” (Wellcome Foundation Pty Ltd v VR Laboratories (Aust) Pty Ltd (1981) 148 CLR 262 at page 281).

Thus, if an inventive step lies in the identification of the true nature of the problem, it is irrelevant whether there is any subsequent inventive step in providing a solution to the problem.

Where the invention lies in identifying the true nature of the problem, this must be clear from the specification, either by assertion or by clear inference (Winner & Anor v Ammar Holdings Pty Ltd 24 IPR 137 at page 141).

In response to an objection of lack of inventive step, an applicant may amend the specification to assert that the invention resides in identifying the true nature of the problem. Such amendments must meet the normal allowability requirements.

However, if the nature of the problem is obvious, it cannot be said that the invention lies in identifying the real nature of the problem (Winner & Anor v Ammar Holdings Pty Ltd 25 IPR 273 at page 295).

If the prior art addresses or discusses the same problem, and identifies its true nature, any argument that an inventive step resides in identifying the true nature of the problem must fail.

If the prior art solves the problem, but has not recognised its true nature:

  • the same solution will result in a novelty objection; otherwise
  • a different solution will involve an inventive step.

Invention in the idea

In order to be patentable, an idea, in addition to having some means of carrying it out, must involve invention (Hickton's Patent Syndicate v Patents and Machine Improvements Co. Ltd (1909) 26 RPC 339).

Some generalised ideas or desiderata are inherently uninventive. Examples of such ideas are automatic operation, convenient arrangement of one's work, an increase in efficiency or combining a number of items into one piece (Pierre Treand's Application [1961] AOJP 2164).

Invention in the purpose

"It is not permissible to claim an article which as an article, requires no inventive ingenuity merely because, if used in a particular way, it will be useful in achieving a particular purpose."(Mullard Radio Valve Co. Ltd v British Belmont Radio Ltd and Juviler (1939) 56 RPC 1 at page 15).

Common general knowledge

What is CGK?

CGK is background knowledge and experience which is known or used by those in the relevant trade. The knowledge is available to all in the trade when developing new products or improving existing products (Minnesota Mining & Manufacturing Co. v Beiersdorf (Australia) Limited (1980) 144 CLR 253 at page 292). CGK is not limited to material which might be memorised and retained at the front of the skilled workers mind but also includes material in the field in which they know exists and would refer as a matter of course, for example standard textbooks, technical dictionaries in the field, and publications specific to the field (ICI Chemicals & Polymers Ltd v Lubrizol Corp 45 IPR 577).

CGK is to be distinguished from “public knowledge” which is the entire body of publicly available information (General Tire & Rubber Co. v Firestone Tyre (1972) RPC 457).

Information that can form part of CGK

What constitutes common general knowledge in a particular matter can only be established by evidence. Examiners are not able to produce such evidence and therefore need to formulate an opinion of what is common general knowledge based on  written information. The following may be used to infer what is common general knowledge:

  • standard texts and handbooks;
  • most dictionaries of standard English;
  • relevant technical dictionaries;
  • concession in the patent application under examination;
  • magazines or other publications specific to the art; and
  • patent specifications, under certain conditions.

However, the material disclosed in such publications does not necessarily constitute common general knowledge. A piece of particular knowledge disclosed in an article, or series of articles does not become common general knowledge merely because it is widely read or widely circulated. Such a piece of knowledge only becomes common general knowledge when it is generally known by the bulk of those who are engaged in the particular art and generally regarded as a good basis for further action (British Acoustic Films Ld v Nettlefold Productions (1936) 53 RPC 221 at page 250 and affirmed in General Tire & Rubber Company v Firestone Tyre and Rubber Company Ltd (1972) RPC 457).

It is important to distinguish between information which is in a publication which may be found by a diligent searcher and information which may be found by such a process and which itself forms part of the CGK (Aktiebolaget Hassle and Astra Pharmaceuticals Pty Limited v Alphapharm Pty Ltd 51 IPR 375). The question for assessing whether an invention is obvious is not whether a diligent search might find publications from which there might have been selected elements which make up a patent (Minnesota Mining & Manufacturing Co. v Beiersdorf (Australia) Ltd (1980) 144 CLR 253). Information in a publication which qualifies as relevant prior art information would need to be regarded by the bulk of those working in a particular field as “generally regarded as a good basis for further action” for the information to regarded as part of the CGK.

In usual circumstances, examiners should not rely on a single patent specification as establishing the state of the common general knowledge.

Where multiple specifications refer to a piece of knowledge, this may be indicative of that knowledge being common general knowledge, especially when the applications are by different applicants. Rather than conducting lengthy searches for the sole purpose of identifying common general knowledge, examiners can consider the possibility of combining documents where the person skilled in the art would be reasonably expected to have done so.

CGK and acknowledged prior art

Acknowledgement of prior art in a patent specification is an admission which carries great weight (Bristol-Myers Squibb Co. v F H Faulding and Co. Ltd 46 IPR 553). However, this does not prevent the applicant or patentee from providing evidence to contradict it (Lockwood v Doric (2007) HCA 21 at paragraph 109; Gerber Garment Technology v Lectra Systems (1995) FSR 492).

​​​​​​​In the first instance, examiners may use a single standard textbook, or another similarly authoritative publication, or a number of patent specifications (published before the relevant priority date) as a basis for asserting that certain information is common general knowledge.

Depending on the art and the issues involved, examiners may be convinced by short submissions from the applicant that a feature was not common general knowledge. Otherwise, the applicant may need to provide more substantial arguments or evidence to tip the balance in their favour. Where examiners have a reasonable basis on which to conclude that a piece of information is common general knowledge, the burden of proof shifts to the applicant to satisfy examiners otherwise.

Examiners are to consider arguments that a piece of information is not common general knowledge based on their merits and should apply balance of probability considerations (see Application of the Balance of Probabilities in Examination).

Prior art, or common general knowledge teaches away from the solution

Where the prior art or the common general knowledge teaches away from the claimed solution, the claims will have an inventive step. However, this will not be the case where the teaching of the prior art is based on an issue which the person skilled in the art would readily:

  • recognise as being erroneous; and
  • be able to correct.

In such cases, examiners must consider the prior art on the basis of the "corrected" disclosure.

Amended Reasons

Amended Reason Date Amended

Published for testing

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